Marginal Utility per DollarSammy’s optimal consumption bundle is at point C, where his marginal utility per dollar spent on clams, MUC/PC, is equal to his marginal utility per dollar spent on potatoes, MUP/PP. This illustrates the optimal consumption rule: at the optimal consumption bundle, the marginal utility per dollar spent on each good and service is the same. At any other consumption bundle on Sammy’s budget line, such as bundle B in Figure 51.3, represented here by points BC and BP, consumption is not optimal: Sammy can increase his utility at no additional cost by reallocating his spending.